Field of the Invention
Embodiments of the present invention relate generally to a multi charged particle beam writing apparatus and a multi charged particle beam writing method, and more specifically, relate to a method for correcting deflection positional deviation of each beam in multi-beam writing, for example.
Description of Related Art
In recent years, with high integration of LSI, the line width (critical dimension) of circuits of semiconductor devices is becoming progressively narrower. As a method for forming an exposure mask (also called a reticle) used to form circuit patterns on these semiconductor devices, the electron beam (EB) writing technique having excellent resolution is employed.
As an example employing the electron beam writing technique, a writing apparatus using multi-beams can be cited. Compared with the case of writing a pattern with a single electron beam, since in multi-beam writing it is possible to irradiate multiple beams at a time (one shot), the throughput can be greatly increased. For example, in a writing apparatus employing a multi-beam system, multi-beams are formed by letting portions of an electron beam emitted from an electron gun pass through a corresponding hole of a plurality of holes formed in the mask, blanking control is performed for each beam, and each unblocked beam is reduced by an optical system and collectively deflected by a deflector so as to irradiate a desired position on a target object or “sample”.
In multi-beam writing, since a large region is irradiated at a time, the amount of positional deviation due to beam deflection varies depending upon the position in the region. Regarding this positional deviation, since multi-beams are collectively deflected in multi-beam writing, it is difficult to perform deflection correction for correcting the positional deviation amount, for each individual beam. Therefore, the positional deviation amount which varies for each individual beam is hard to be corrected. Particularly, when performing writing processing while moving, since the deflection position changes every second, it becomes more difficult to carry out deflection correction for each individual beam.
In connection with the multi-beam technique, there is disclosed a technique where a tracking operation in response to a stage movement is performed while being scanned by continuous multi-beams in one direction by raster scanning (refer to, e.g., Japanese Published Unexamined Patent Application (JP-A) No. 05-166707).